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Патент USA US3088944

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3,088,934
p
United States Patent 0 '
lCe
Patented May 7, 1963
2
1
3,088,934
METHOD OF PREPARING A DIISOCYANATE
BASED LAMINATING RESIN
Angelo P. Bonanni, 138A Haddon Hills Apts.,
Haddon?eld, NJ.
No Drawing. Filed Mar. 24, 1960, Ser. No. 17,440
1 Claim. (Cl. 260-775)
(Granted under Title 35, U8. Code (1952), sec. 266)
rudder and ?n tips, fuel cell backing boards and various
missile components.
It is therefore another object of this invention to pro
vide a method for making a resin that is hard and yet is
able to withstand abrasion.
Another object is to provide a resin for use as an in
terlayer material in laminates whereby a substantial ?ex
ural strength is imparted to the laminate.
Yet another object is .to provide a method for the prep
The invention described herein may be manufactured 10 aration of a polyurethane laminating resin having stable
and used by or for the Government of the United States
chemical and physical properties that are easily dupli~
of America for governmental purposes without the pay
cated.
ment of any royalties therein or therefor.
Other objects and many of the attendant advantages of
This invention relates to the making of a new chemi
this invention will be readily appreciated as the same be
cal type of laminating resin and more particularly relates 15 comes better understood by reference to the following
to a process for reacting a polyisocyanate directly with
a glycol to form a new type of arti?cial resin.
'Resins known under the prior art have use in a wide
variety of applications; however, they have all had one
or more serious de?ciencies for practical use, such as 20
brittleness, lack of abrasion resistance, lack of solvent re
sistance and a very short stability.
‘In one particular case, the preparation of a new type
of resin was attempted by reacting an unsaturated diol di
rectly with a polyisocyanate in the presence of styrene 25
or some other unsaturated monomer. The purpose of
the styrene was to limit the degree of polymerization.
detailed description. -
The formulation of a polyurethane resin, which pos
sessed stable chemical and physical properties suitable for
the preparation of a glass cloth laminate, was established
through. the ?ne control of the reaction exotherm caused
by the cleavage of the double bond between the nitrogen
and carbon. atoms of the diisocyanate radical. This
cleavageis triggered by the migration of the proton from
the hydroxyl radical of the glycol. This is illustrated by
the following reaction of 2,4-meta toluene diisocyanate
with 2-butene-‘l,4 diol.
OH:
0
ll
L
C:
This method, although producing a polyurethane resin
which exhibited stable chemical and physical properties
suitable for the preparation of a glass cloth laminate,
was dif?cult to ‘control because of the reaction eXotherm.
Hence, it was dif?cult to predict and duplicate polyure
thane laminating resins having stable chemical and
physical properties.
Heretofore, in order to avoid such a large heat of re
action, it was the practice to ?rst synthesize the ester
from a suitable dicarboxylic acid and unsaturated diol
and then react this ester from a suitable dicarboxylic acid
and unsaturated diol and then react this ester with the
diisocyanates to make the polyurethane resins. This re
action between the ester and the diisocyanate, although
easier to control, proved to be unsatisfactory for the prep
aration of laminates since the polyurethane resins were
soft and rubbery resembling unvulcanized natural rubber
in appearance and consistency.
The process of manufacturing glass laminated forms
for aeronautical use requires that the laminate be pre
heated at an elevated temperature before molding into the
complex forms required for such use. Thus, a ilaminate
interlayer for this application must remain su?iciently
pliable and soft during the forming operation in order to
permit forming of the laminate.
It is an object of this invention to prepare a laminating
resin for use in combination with glass reinforcements to
produce structural laminates for such things as radomes,
Since this reaction is exothermic in nature, the reaction
is carried out inside of an ice bath. lIn this way, it is pos
sible to retard the reaction rate of the diisocyanate. in
order to prevent freezing of the diisocyanate, the solu
tion is constantly stirred with a mechanical stirrer or the
like. The glycol is added dropwise to retard the reaction
rate between the diisocyanate and itself wherein the oper
ator is able to control :the degree of polymerization.
Once the reaction is initiated, an aromatic solvent is add
ed to also aid in retarding the polymerization of the resin.
This reaction is allowed to continue until there is a sig
ni?cant drop in temperature which signi?es the end of
polymerization. The reaction exotherm produced de
pends upon the type of glycol used in the reaction with
the diisocyanate. By employing glycols containing four
carbon atoms, resins were formulated which, when used
in the formation of glass laminates, imparted a ?eXural
strength of over ‘90,000 psi to the laminates. The in
vention is further illustrated by the following speci?c
examples.
Example 1
191.6 grams of 2,4 tolylene diisocyanate is added to
a reaction ?ask. The ?ask is then packed in ice in order
to lower the temperature of the diisocyanate to its freez
ing point. ‘88 grams of 2-butene-1,4-diol was slowly add
ed with stirring. To retard polymerization of the resin,
once the reaction is initiated, 139.8 grams of benzene is
3,088,934
'
4
a
added at intervals of ?ve minutes in 5 to 10 ‘cc. portions.
Example III
The solution is stirred throughout the time of reaction and
191.6 grams of 2,4-tolylene diisocyanate and 106.1
grams of diethylene glycol were reacted in the presence
drop in temperature is noted which signi?es a termination
of 148.8 grams of benzene as described in Example I.
of reaction. The reaction exotherrn produces a maximum
The laminate prepared from this resin had a thickness
temperature of approximately 40° C. lasting for approxi
of 0.090 inch, a ?exural strength of 83,000 lbs. per square
mately ten minutes. At this point, the solution takes on
inch, and a modulus of 4.52><10+6.
a hazy yellow appearance which instantly turns to crystal
After immersion in boiling water for two hours, this
clear amber. The resin thus formulated had a consistency
similar to honey and a pot life of approximately 4 to 10 laminate possessed a ?exural strength of 35,900 lbs. per
square inch, and a modulus of 252x10“.
5 hours.
'
The resins, formulated with glycols having a four-car
The glass laminates were fashioned from this resin by
bon chain, produced laminated panels that were consistent
immersing, singularly, twelve pieces of glass fabric in the
in imparting substantial ?exural strength to the laminates.
resin and then laying them up 90° to one another. This
Obviously many modi?cations and variations of the
lay-up was wrapped in a sheet of cellophane. The en 15
present invention are possible in the light of the above
tire assembly was then placed between two highly polished
teachings. #It is therefore to be understood that within
steel platens, which had been heated to 300° F., and sub
the scope of the appended claim the invention may be
jected to a load of approximately 1100 lbs. under a 50
practiced otherwise than as speci?cally described herein.
ton capacity standard molding press. After twenty-?ve
I claim the following:
minutes, the load was reduced to the extent that the lami 20
An improved process for the manufacture of a lami
nating assembly remained in a ?xed position under a very
nating resin suitable for use in making glass laminates,
slight load. The laminate was allowed to cool to 100°
said method comprising the steps of:
F. under these conditions, and it was then removed from
(1) reacting at a temperature of 20° C. 1.1 to 11.6
the press.
moles of ‘2,4-meta toluene diisocyanate with 1 to 1:6
This laminate had a thickness of 0.092 inch, a ?exural
moles of a polyhydric alcohol selected from the
strength of 90,080 lbs. per square inch, and a modulus
group consisting of 2-butene-1,4-diol, butane-1,4 diol,
of elasticity of 4.35 X 10+6.
diethylene glycol, and triethylene glycol wherein the
After immersion in boiling water for two hours, this
said glycol is added at a rate of 1 cc./min.;
laminate possessed a ?exural strength of 61,400 lbs. per
(2) mixing 1 to 3 moles of benzene therewith for re
square inch, and a modulus of elasticity of 4.64><10+6. 30
the stirring continued for 30 additional minutes after a
Example 11
287.1 grams of 2,4 tolylene diisocyanate and 135.2
grams of butane-1,4-diol were reacted in the presence of
211.2 grams of benzene as described in Example I.
The laminate formed from this resin had a thickness of
0.089 inch, a ?exural strength of 92,800 lbs, per square
inch, and a modulus of elasticity of 4.14><10+6.
After immersion in boiling water for two hours, this
laminate possessed a flexural strength of 53,400 lbs. per
square inch, and had a modulus of 4.71 X 10+“.
tarding polymerization of the said resin by selective
ly dissolving the resin without dissolving either the
diisocyanate or the glycol;
(3) maintaining the reaction below 42° C. thereby
limiting the degree of polymerization of the resin.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,511,544
2,692,874
2,855,421
Rinke et al. __________ __ June 13, 1950
Langerak ____________ __ Oct. 26, 1954
Bunge et a1. __________ __ Oct. 8, (1958
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